Experts predict a 8.3 Billion population by 2030,long before that,Nations will act to preserve themselves and their people.This is how I see it unfold,
2014 US economy ruined, US military although technologically superior than its adversaries can no longer maintain a drawn out conflict.Peaceniks and Socialist programs fill the Govt. agenda. EU in similar shape,Muslim immigrants make a very large minority in most of EU,and majority in some major cities,forcing lawmakers there to back away from any ME interventions. In 2013 the Syrian issue has been resolved by a Turkish invasion, Assad is out of power,and Israel reluctantly forms a Palestinian state from the West Bank, but not Gaza,which has become an Egyptian protectorate.Iran has gained Nuclear weapons and no one fired a shot, iran wisely doesnt threaten anyone with the warheads and adopts a MAD policy with Israel. China and India have massive populations that cannot develop within their borders,The opening shots begin in Korea.
North Korea has a coup, the people begin defecting enmasse to the South, and are fired upon,South Korea intervenes.
China swarms into Korea to stop the S. Korean assault,US and Japanese forces attempt to stop the Chinese, with a large fleet presence and reinforcement of ROK positions. China responds with a limited Nuclear attack on US fleet at sea, destroying several capitol ships and a Non nuclear barrage of Japan.
Doves in US protest,govt. sees that US cannot maintain a drawn out conflict and signs armistice within three weeks,Korea is placed under Chinese mandate.Japan collapses into chaos.
Russia sees Chinese designs on its eastern territory and mobilizes. Spark comes from Chinese intervention in Indochina,and continuous occupation of Korea.which is starving.Russian forces penetrate deep into Manchuria and inner Mongolia. China is warned concerning Nuclear weapons. Huge tank battles manifest inside China,with Russia pushing deeper, finally China nukes the Russian forces within China.